Electric switch



March 5, 1929. L. A. M. PHELAN ELECTRIC SWITCH Original Filed Sept. 22, 1924 Patented Mar. 5, 1929.

UNITED STATES PATENT OFFICE.

LOUIS A. M. PHELAN, OF BELOIT, WISCONSIN, ASSIGNOR, BY MESNE ASSIGNMENTS, TO TIME-O-STAT CORPORATION, OF ELKHART, INDIANA, A CORPORATION 01' MARY.

LAND.

ELECTRIC SWITCH.

Original application fled September 22, 1924, Serial No. 739,006. Divided and this application fled October 29, 1925.

My invention relates to automatically operated electric switches and more particularly to those having enclosed contacts which make and break the circuit and which are capable of handling substantlal quantities of current at commercial voltages.

While I shall describe my invention as having particular application to a type of switchprovided with enclosed contacts, it will nevertheless be understood that any type of switch may be used, which is automatic in operation and may be actuated by an actuating force imparted by a device provided for the purpose, notwithstanding that the former type of switch may be preferable on account of its durability and simplicity of design.

The present invention, however, is a division of my copending application, Serial Number 739,006, filed September 22nd, 1924 and refers more particularly to a pressure 0 erated switch which comprises a pressure e ementthat provides an actuating force for the electric switching mechanism for opening and closing the electric circuit as the pressurev element moves by reason of pressure changes that ma influence it.

The switch w ich I employ is preferably of the tiltable mercury contactor type wherein the co-operating contact members or electrodes between which the circuit is made and broken, are fixed in position and are adapted to be bridged by a conducting body, such as'mercury, that is moved to and fro by an actuating element at the expense of very little energy, such as may be available when a pressure change of a small amount may occur. The co-operating con tact members of my switching device are spaced a suitable distance from one another to preclude premature electric discharges between them, and they are completely enclosed in a sealed container, thereby insuring them against corrosion, contamination and deterioration. v

- An object of my invention resides in the provision of an improved form of pressure operated switch of the tiltable mercury contactor type wherein novel means are provided for resilientl supporting the mercury contactor and or absorbing the kinetic Serial No. 85,509.

energy of the movable body of mercury contamed in the contactor upon operation of the switch. A pivotal mounting which is connected to the pressure element, is provided for the mercury contactor, allowing the contactor to be tiltably carried so'that 1t is sensitive to the slightest movement by the pressure element.

A further object of my invention is to provide the resilient supportin means for the mercury contactor in the firm of current conductors coextensive with the lead-in wires whereby a dual function is provided: vlz, that of absorbing the kinetic energy of the movable body of mercury within the contactor, which places the opposite side of this supporting means under tension to assist in the return of the contactor to its normal position, and secondly, that of carrying the electric current to the lead-in wires which eliminates the usual wires heretofore employed.

A still further object of my invention is to provide an improved form of connection, between the pivotal mounting of the mercury contactor and the pressure element, whereby an exceedingly fine adjustment of the efiective pressures at which the circuit will be opened and closed may be accurately obtained.

In accomplishing these and other objects and advantages of my invention, I am able to provide an exceedingly simple and compact arrangement of the parts in a device which is durable, reliable and efficient. When controlling motor circuits, I have found it unnecessary to employ relays or like devices, as the switching mechanism which I use has a large current carrying capacity and is capable of quick and accurate operation by the expenditure of very little energy.

In the drawings:

Figure 1 is a front elevational view of a device embodying my invention with the cover omitted so that the various operating parts of the structure will be more clearly illustrated Fig. 2 is a view of the same, looking from the rear thereof;

Fig. 3 is a perspective view of the mercury contactor and the mounting provided therefor; and

Fig. 4 is adetail view of the mechanism employed herein providing a sensitive adjustment of the action of the pressure element on the mercury contactor.

The device illustrated herein and embodying oneof the preferred forms of my invention is adapted to be operated by a pressure element instead of a thermostatic element as described in the parent application. By referring to the drawings, it will be noted that one end of a Bourdon pressure gauge 5 is connected to a nipple 6,,while the opposite end has a link or rod 7 fixed thereto, as indicated at 8. A "link 9 is pivotally connected to a bracket 10.

In this device the mercury contactor 12 comprises a sealed chamber 14, preferably a glass tube, in which cooperating electrodes 15 and 16 may be sealed. The container 14 is evacuated and contains a body of mercury 17, as well as an inert gas. The container 14 is of tubular form having its longitudinal axis placed approximately horizontal; The electrodes or contact members 15 and 16 are preferably made of pure metal and are disposed on one side of the axis of rotation of the mounting for the mercury contactor. A tiltable mounting is provided for the mercury contactor, which allows mercury 17 to ride on a. lower annular surface of container 14 and, when tilted to the right'of Fig. 1, it serves to establish an electric circuit between the electrodes 15 and 16. When the contactor 12 is tilted in the direction illustrated in Fig. 1, the mercury 17 flows to the other end of container 14, and

thereby opens the circuit between the cooperating contact members or electrodes 15 and 16. Electrode 15 is connected in electrical circuit with a leading-in wire 18, which is embedded in a glass shank 19, thereby providing a substantial support for the leading-in wire 18. Similarly, the electrode 16 is connected to a leading-in wire 20, which is likewise embedded in a glass shank 21. Thus, it will be seen that electrodes 15 and 16 are fixed and are stationary with respect to each other.

With respect to the mounting of mercury contactor 12, I provide substantially the same novel form of tiltable mounting and resilient support as is disclosed in the aforementioned co-pending application. This tiltable mounting and resilient support comprises a rigidly fixed bracket 24 secured to an insulating projection 25, by means of screws 26, which projection 25 is preferably integrally formed with an insulating base 27. Insulating base 27 may be secured to the back wall 28 of housing 30 by means of suitable screws 31. Bracket 24 projects forwardly and then downwardly, having a portion 32 which is apertured at this lower end, as indicated at 33. An annular clamping ring 34 securely grips the mercury contactor 12 at a point substantially midway of its ends. The clamp 34 is brought tightly against the glass container 14 by means of a screw 35 and a. cooperating nut 36, as indi- I cated in Figs. 1 and 2. One of the lower ends, designated 37 forms a downwardly projecting apertured extension, while the other end of said clamp 34 is adapted to have fixed thereto one end of a rod 38, which may be seen in Fig. 3. The opposite end of this rod 38 is pivoted in the lower apertured end 33 of the portion 32 of bracket 24. From the description thus far, it will be seen that I provide a pivotal mounting for the mercury contactor 12 which is located substantially at a point between the ends of the contactor. The arrangement reduces frictionallo sses to a minimum, because friction at the pivot point of contactor 12 is practically negligible. Apertured extension 37 of clamp 34 is adapted to connect to the upper end of the arm 9 by means of a rod 39. Arm 9 has its upper vertical end 40 also apertured which permits rod 39 to be accurately adjusted with respect to the arm 9 and the position of the contactor 25, to compensate for any mechanical or manufacturing inaccuracies.

I have also disclosed a balance support for the mercury contactor 12, which includes means for resiliently supporting the contactor at its ends. In addition to accomplishing this purpose, said means further functions to absorb the kinetic energy of the movable body of mercury 17 in the container 14 when the switch is actuated. This means comprises a pair of leaf spring members 42 and 43, best illustrated in Fig. 3. Each leaf spring is provided with an extension 44, which is adapted to connect with the terminals 45 of the electric circuit. The leaf spring extends upwardly and then outwardly, resulting in forwardly projecting arms 46. The end of each arm 46 is apertured for the purpose of receiving, in fixed relation, the projecting tips of the leading-in wires 18 and 20. The spring members 42 and 43 are in electrical conducting relation between the leading-in wires 18 and 20 and the terminal; 45 of the circuit. This arrangement eliminates flexible leads, and further elimi- Ilates the influence which tension in flexible leads would have on the movement of the contactor 12 when operated. Furthermore,

these resilient leads tend to restore the con open or close the circuit at a predetermined pressure, bracket '10 is provided with a longitudinal elongated slot in the arm 56 thereof. A supporting post 57 extends forwardly from the rear wall 28 of housing 30.-

A screw 58 may pass through the slot 55 and thread into the outer end of post 57. The right angle arm 60 of bracket 10 is adapted to receive a screw 61, which is locked to this arm, but which is adapted for movement into and out of supporting post 57. The head 62 of screw 61 is disposed adjacent to an opening 63 in the side wall of housing 30. Such a provision permits the insertion of a screw driver, or other sharp pointed instrument, for engagement with the screw head 62 to move bracket 10 relative to its point of support, which may be designated the screw 58 riding in slot 55. It will'be observed that with the lever arm 9 pivoted at 64 to the lower end of arm 56 of bracket 10, any movement of this bracket will vary the position of the lever arm with respect to a transverse extension 65 on the rod 7. The distance between projection 65 (or rod 7 and the adjoining edge of the lever arm 9 may be readily varied by such adjustment, so as to vary the pressures at which the Bourdon gauge will operate to tilt the mercury contactor 12, either to circuit closing position, or to circuit 0 ening position. When it is desired for t e device to operate at a desired pressure, the tilting position of the contactor is varied, this, in turn, changing the position of the lever arm 9 with respect to the right an ular projection 65, so that a greater or sma ler movement of the link 7 will be required, it depending on the pressure at which the device is to operate.

Various other embodiments and modifications of the structural details shown herein may be apparent to those skilled in the art without departing from the spirit and scope of the invention.

I claim:

1. An electric switch comprising a mercury contactor tiltably mounted upon a pivot, a pressure element ada ted to tilt said contactor about its pivot or opening and closing an electric circuit through said contactor, and an adjustable connection loosely connected between said contactor and said pressure element and independently mounted thereof for predetermining the effective operating pressure of said pressure element.

2. An electric switch comprising a mercury contactor tiltable about a pivot, a pressure element adapted to tilt said contactor to control an electric circuit therethrough and an adjustable connection loosely connected between said contactor and said pres sure element and independently mounted thereof for predetermining the efi'ective cury contactor tiltable about a pivot, a pressure element having a loose engagement with and for tilting said contactor at predetermined pressures to control the electric circuit through said contactor, and calibrating means for predetermining said pressures including a movable member, a connection between said movable member and said switch, and an adjustable fastening associated with said movable member for varying the position of the latter with respect to said pressure element.

4. An electric switch comprising a tiltable mercury contactor, a pressure element having a loose engagement with and for tilting said contactor at predetermined pressures to control the electric circuit through said contactor, and calibrating means for said pressure element including a pivotal lever arm movable with respect to one end. of said pressure elements for varying the distance therebetween.

5. An electric switch comprisin a tiltable mercury contactor, a housing therefor, a pressure element having a loose engagement with and for tilting said contactor at predetermined pressures, and calibrating means accessible through an opening in said housing for predetermining said pressures comprising a pivotal lever arm extending from said contactor, a bracket suitably supported within said housing, and an adjustable screw associated with said bracket for varying the position of said pivotal lever arm with respect to said pressure element.

6. An electric switch comprising a tiltable mercury contactor, a housing therefor, a pressure element having a loose engagement with and for tilting said contactor at predetermined pressures, and calibrating means for predetermining said pressures comprising a forwardly projecting support, a slotted bracket slidable on said support, and a pivotal lever arm associated with said bracket and connected to said contactor the movement of said bracket on said support varying the position of said pivotal lever arm with respect to said pressure element.

7. An electric switch comprising a tiltable mercury contactor, a housing therefor, a pressure element having a loose engagement with and for tilting said contactor at predetermined pressures, and calibrating means for predetermining said pressures comprising a support, a slotted bracket movably mounted on said support, a connection in close proximity to said pressure element extending between said contactor and said bracket, and an adjustable screw element for moving said bracket on said support whereby to vary the distance between said connection and said pressure element.

8'. An electric switch comprising a merin one direction onilfy whereby said means cury contactor tiltable about a pivot, a prespredetermine the e ective operating pressure element adapted to tilt said contactor surejof said pressure element for controlling 10 and loosely connected calibrating means for the electric circuit through said contactor.

5 adjusting the relative position of said pres- In witness whereof, I have hereunto subsure element with respect to said contactor, scribed my name.

said calibrating means operating positively LOUIS A. M. PHELAN. 

